We will coordinate the study through the CRC. The women will have to come in only twice, to have the monitor placed and then taken off three days later. A blood sample will be collected at each visit. Meals and snacks will be provided for each day of the study, specially packaged, to supply an equivalent amount of calories for each subject. These will meet the nutritional requirements for both the mother and the fetus. Women will do separate fingerstick blood sugar measurements using a capillary glucometer four times a day, to ensure the accuracy of the sensor's readings.